Generally, this kind of component mounting apparatus has been known to have various structures. For instance, there is an apparatus with a structure as shown in FIG. 10 (see, e.g., Japanese unexamined patent publication No. H07-303000).
As shown in FIG. 10, an apparatus 231 is a component mounting apparatus for mounting components 232 such as bare IC chips onto substrates 233, and in a rear portion (back side) of a base 234 as viewed in this figure, there are provided a mounting head 235 for holding and mounting the components 232 onto the substrates 233, and an X-axis robot 236 which supports the mounting head 235 in such a way as to allow back-and-forth movement in an X-axis direction as viewed in the figure. On the base 234 below the X-axis robot 236, a slide table 237 movable in a Y-axis direction is located, and on the slide table 237, a holding base 238 for placing and holding the substrates 233 is located. Moreover, on the right-hand side of the base 234 in the X-axis direction as viewed in FIG. 10, a component feed device 249 which houses a plurality of components 232 in a feedable manner is located.
Moreover, in a front portion (near side) of the slide table 237 on the base 234 as viewed in FIG. 10, a substrate transportation apparatus 241 for transporting the substrates 233 along the X-axis direction as viewed in this figure is located. The substrate transportation apparatus 241 includes a loader 239 for transporting the substrates 233 from a right-side end portion of the base 234 along the X-axis direction as viewed in FIG. 10 to the slide table 237 and for loading the substrates 233 onto the holding base 238 on the slide table 237, and an unloader 240 for transporting the substrates 233 from the slide table 237 to a left-side end portion of the base 234 along the X-axis direction as viewed in this figure and for unloading the substrates 233 from the holding base 238 on the slide table 237.
Description will be given of a mounting operation performed in such a component mounting apparatus 231. A substrate 233 transported by the loader 239 is fed to the holding base 238 which is moved by the slide table 237 so as to be positioned between the loader 239 and the unloader 240, and is held by the holding base 238. Then, the substrate 233 held by the holding base 238 is moved by the slide table 237 so as to be positioned below the X-axis robot 236. At the same time, the component feed device 249 feeds a component 232 to the mounting head 235, and the mounting head 235 holding the component 232 is moved upward by the X-axis robot 236 for mounting the component 232 onto the substrate 233. Such mounting operation is repeated so as to mount a plurality of the components 232 onto the substrate 233. Then, the holding base 238 holding the substrate 233 with a plurality of components 232 mounted thereon is moved by the slide table 237 so as to be positioned between the loader 239 and the unloader 240, and the substrate 233 is transported and unloaded by the unloader 240.
Herein, a fragmentary enlarged cross sectional view showing a structure of the substrate transportation apparatus 241 in the component mounting apparatus 231 is shown in FIG. 11, and description is given of the structure with reference to FIG. 11.
As shown in FIG. 11, the loader 239 and the unloader 240 included in the substrate transportation apparatus 241 are respectively equipped with two transportation rails 239a and 240a for supporting respective end portions of the substrate 233 in the Y-axis direction as viewed in this figure in a transportable manner. Moreover, by the loader 239 and the unloader 240, the substrate 233 is transported in a substrate transportation direction A, which is a direction facing leftward in the X-axis direction as viewed in FIG. 11.
Further, as shown in FIG. 11, the substrate transportation apparatus 241 is equipped with a loading arm 242 for releasably holding the substrate 233 that is transported to the vicinity of end portions of the respective transportation rails 239a in the loader 239 on a side of substrate transportation direction A and for transferring the substrate 233 onto the holding base 238 positioned between the loader 239 and the unloader 240, and an unloading arm 243 for releasably holding the substrate 233 held on the holding base 238 in a state of being positioned at the aforementioned position and for transferring the substrate 233 to the vicinity of the end portions of the respective transportation rails 240a in the unloader 240 on a near-side of substrate transportation direction A. Moreover, the loading arm 242 and the unloading arm 243 are movable in an integrated state along the Y-axis direction as viewed in FIG. 11, and are also movable separately in a vertical direction.
Next description discusses feed and discharge operations of the substrate 233 onto/from the holding base 238 in thus-structured substrate transportation apparatus 241.
First, FIG. 12A, FIG. 12B, FIG. 12C and FIG. 12D show schematic explanatory views of the feed and discharge operations. It is to be noted that in FIG. 12A to FIG. 12D, a newly fed substrate 233 is referred to as substrate 233A, and a component-mounted substrate 233 is referred to as substrate 233B.
As shown in FIG. 12A, in the component mounting apparatus 231, upon completion of a mounting operation of component 232, substrate 233B with the component 232 mounted thereon is moved with the holding base 238 to between the loader 239 and the unloader 240 by the slide table 237, while substrate 233A on which a next component 232 is mounted is transported in substrate transportation direction A by the loader 239. Then, the loading arm 242 and the unloading arm 243 are moved along substrate transportation direction A so that the loading arm 242 is positioned above the substrate 233A and the unloading arm 243 is positioned above the substrate 233B, and after being moved, the loading arm 242 is moved downward to hold the substrate 233A, while the unloading arm 243 is moved downward to hold the substrate 233B.
Next, as shown in FIG. 12B, the loading arm 242 is moved upward in a state of holding the substrate 233A, while the unloading arm 243 is moved upward in a state of holding the substrate 233B. Then, as shown in FIG. 12C, the loading arm 242 and the unloading arm 243 are moved in substrate transportation direction A, so that the substrate 233A held by the loading arm 242 is positioned above a holding base 238 and the substrate 233B held by the unloading arm 243 is positioned above the vicinity of an end portion of the unloader 240. It is to be noted that at this point, the component 232 is mounted on the substrate 233B, and so a movement speed during this movement is set to be a speed which prevents this mounted component 232 from being displaced from its mounted position by vibration and the like generated during the movement, i.e., a speed lower than a normal movement speed.
Then, as shown in FIG. 12D, a downward movement operation of the loading arm 242 and the unloading arm 243 is performed to transfer the substrate 233A onto an upper surface of the holding base 238, while the substrate 233B is transferred to the unloader 240. Then, the loading arm 242 is released from the state of holding the substrate 233A and the loading arm 242 is moved upward, while the unloading arm 243 is released from the state of holding the substrate 233B and the unloading arm 243 is moved upward. After that, the substrate 233B is transported in the substrate transportation direction and discharged from the component mounting apparatus 231 by the unloader 240. At the same time, the holding base 238 that held the substrate 233A is moved by the slide table 237, and a mounting operation for mounting each component 232 on the substrate 233A is started.
Further, a timing chart for such feed and discharge operations of the substrate 233 is shown in FIG. 13. FIG. 13 shows a time relationship among execution/stoppage of the component mounting operation, execution/stoppage of the movement operation of the slide table 237, respective vertical movement height positions of the loading arm 242 and the unloading arm 243, execution/stoppage of the holding operation of the substrate 233 by the loading arm 242 and the unloading arm 243, and execution/stoppage of the movement operation of the loading arm 242 and the unloading arm 243 along substrate transportation direction A. Moreover, respective time points T1 through T10 represent significant time points of respective operations. As shown in FIG. 13, time points T3 to T4 indicate the state in FIG. 12A, time point T5 indicates the state in FIG. 12B, time point T6 indicates the state in FIG. 12C, and time points T7 to T8 indicate the state in FIG. 12D.